【摘要】 通过急性毒性和胁迫试验,探讨氨氮对泥鳅(Misgurnus anguillicaudatus)的急性毒性及对其肝、鳃超微结构的影响,为其养殖水质指标管理提供理论依据。急性毒性试验结果表明,在水温(25±1)℃、pH(8.1±0.1)、溶解氧(6.5±0.5)mg/L时,水中氨氮浓度越高,泥鳅的死亡率越高,其96 h LC50总氨浓度(TAN)为164.4 mg/L,非离子氨(NH4+-N)浓度为2.22 mg/L。胁迫试验结果表明,随着氨氮浓度的变化,试验组泥鳅鳃组织在21 d后出现不同程度的变化;其中,50 mg/L和150 mg/L浓度组的泥鳅鳃丝表面出现分泌物,细胞水肿;250 mg/L组鳃丝表面分泌物增加,鳃小片聚拢,上皮细胞水肿加剧;450 mg/L组鳃上皮坏死。泥鳅肝脏细胞超微结构在不同氨氮浓度下也出现不同程度的损伤,50 mg/L和150 mg/L组的泥鳅肝脏细胞线粒体扭曲变形,细胞核变形,核膜肿胀;250 mg/L组肝脏细胞胞浆空泡化,残存细胞器的结构不完整;450 mg/L组出现大量肝脏细胞凋亡。随着氨氮胁迫浓度的不断升高,鳃组织和肝细胞超微结构的受损程度逐渐严重,且损伤不可逆转。更多还原

【Abstract】 In order to provide scientific theoretical basis for water quality management during loach(Misgurnus anguillicaudatus) culture,an acute toxicity test of ammonia nitrogen and ammonia-N stress on the microstructures of gill and liver of loach were studied.Results of acute toxicity test showed that under water temperature(25±1)℃,pH(8.1±0.1),dissolved oxygen(6.5±0.5)mg/L,the higher the concentration of water ammonia nitrogen,the higher the motality of loach;96 h LC50 of total ammonia concentration(TAN) and nonionic ammonia(NH+4-N) were respectively 164.4 mg/L and 2.22 mg/L.Results of the stress test showed that with the ammonia-N concentration increased,loach gills appeared different levels of injuries after 21 d.In 50 mg/L and 150 mg/L groups,the gills of loach appeared secretions and cells edema.In 250 mg/L group,secretion on surface of gill filaments increased,gill lamellae gathered together and edema of epithelia cells was sharpen.In 450 mg/L group,there was cell necrosis of gills.The ultrastructure of loach liver cell under different concentrations of ammonia nitrogen appeared varying degrees of damage.In 50 mg/L and 150 mg/L groups,mitochondria distorted,and nuclei deformed with nuclear membrane swelling.In 250 mg/L group,liver cell structure was badly damaged,and there was cytoplasm vacuolization and incomplete structure of the organelles.In 450 mg/L group,massive liver cells appeared apoptosis.With ammonia-N concentration increased,the damage in gill tissue and liver cells seemed gradually serious,and the damage was irreversible.更多还原